The present invention provides novel oligomeric vinyl esters prepared from polyepoxides of the co-oligomerization product of a mixed cyanate of a polyphenol and an aromatic polyamine.
Vinyl esters are the reaction product of about equivalent amounts of a monounsaturated monocarboxylic acid and a polyepoxide. One class of vinyl esters is described by Bearden in U.S. Pat. No. 3,367,992 where dicarboxylic acid half esters of hydroxyalkyl acrylates or methacrylates are reacted with polyepoxide resins. Bowen in U.S. Pat. Nos. 3,066,112 and 3,179,623 describes the preparation of vinyl esters from monocarboxylic acids such as acrylic and methacrylic acid. Bowen also describes alternate methods of preparation wherein a glycidyl methacrylate or acrylate is reacted with the sodium salt of a dihydric phenol such as bisphenol A. Vinyl ester resins based on epoxy novolac resins are described in U.S. Pat. No. 3,301,743 to Fekete et al. Fekete et al describes vinyl esters where the molecular weight of the polyepoxide is increased by reacting a dicarboxylic acid with the polyepoxide resin as well as acrylic acid, etc. in U.S. Pat. No. 3,256,226. Other functional compounds containing a group which is reactive with an epoxide group, such as an amine, mercaptan and the like, may be utilized in place of the dicarboxylic acid. All of the above-described compositions, which contain the characteristic linkages ##STR1## and terminal polymerizable vinylidene groups are classified as vinyl esters and are incorporated herein by reference.
The vinyl ester is typically combined with a reactive diluent, a copolymerizable vinyl monomer, to alter the viscosity of the mixture, to vary the properties of the cured coating, or for other known reasons. Most any vinyl monomer may be employed which is copolymerizable with the unsaturated groups of the vinyl ester. Such monomers include both monovinyl and polyvinyl monomers. Typical monomers include the alkenyl aromatic monomers such as styrene, .alpha.-methylstyrene, vinyltoluene, t-butyl styrene and the like; and alkyl and hydroxyalkyl esters of acrylic and methacrylic acid such as methyl, ethyl, propyl, butyl, cyclohexyl and hydroxyethyl, hydroxypropyl and hydroxybutyl acrylates and methacrylates. In addition to the above, other monomers are especially useful for ultra-violet light curable systems such as 2-acetoxyalkyl acrylates; pentaerythritol di-, tri- or tetra-acrylates and the like and may be added in any order.
The vinyl ester and copolymerizable vinyl monomer blend is a crosslinkable vinyl ester resin which is cured by mixing in a free radical forming catalyst in an amount ranging from 0.1 to about 5 percent by weight, preferably 1 and 2 percent by weight. Examples of these catalysts are benzoyl peroxide, tertiary butyl hydroperoxide, methylethylketone peroxide and the like. It is frequently of value to add an accelerator such as N,N-dimethylaniline, cobalt naphthenate and the like.
Preparation of hydroxyaromatic oligomers containing triazine groups and polyepoxides thereof is taught by R. E. Hefner, Jr. in U.S. Pat. No. 4,489,202 issued Dec. 18, 1984 which is incorporated herein by reference. The process of this invention uses an easily prepared mixed cyanate of a diphenol or polyphenol. More specifically, the process disclosed therein comprises reacting at least one material having an average of more than one aromatic hydroxyl group per molecula with at least 0.01 but not more than 0.95, preferably from about 0.05 to about 0.55 moles of cyanogen halide or mixture of cyanogen halides per aromatic hydroxyl group in the presence of a suitable base in a quantity of from about 0.01 to about 1.1, preferably from about 0.05 to about 0.6, moles per aromatic hydroxyl group at a temperature and time sufficient to essentially complete the reaction and thereafter recovering the resultant cyanate mixture; trimerizing the cyanate mixture in the presence of a suitable trimerization catalyst at a temperature and time to essentially complete the trimerization reaction; epoxidizing the resultant trimerized product in a conventional manner by reaction with an epiholohydrin with subsequent dehydrohalogenation with a basic-acting material and finally recovering the resultant triazine functional glycidyl ether product. Excellent control over the molecular weight and content of triazine groups is provided by this process. The epoxy resin compositions of this invention possess unusually high thermal stability as well as excellent overall physical and mechanical properties.
Preparation of hydroxyaromatic oligomers containing triazine and oxazoline groups and polyepoxides thereof is disclosed in U.S. Pat. No. 4,487,915 issued Dec. 11, 1984. The process disclosed therein uses the aforementioned mixed cyanate of a diphenol or polyphenol. Co-oligomerization of this cyanate mixture with an epoxy resin such as the diglycidyl ether of bisphenol A, provides hydroxyaromatic oligomers containing both triazine and oxazoline groups. Oligomers prepared from co-oligomerization of the mixed cyanate of a diphenol with an epoxy resin using mole ratios of epoxy groups to cyanate groups of about 1 to 10 to about 1 to 40 or more are most preferred in the process of this invention. The oligomers, and unreacted diphenol, if any, are then epoxidized using methods well known in the art. The epoxy resin compositions of this invention possess excellent thermal stability as well as enhanced mechanical properties.
Preparation of advanced epoxy resin compositions containing triazine groups or both triazine and oxazoline groups is taught by R. E. Hefner, Jr. in allowed application Ser. No. 582,415 filed Feb. 22, 1984. In the process disclosed herein the respective triazine-containing or triazine-containing and oxazoline-containing hydroxyaromatic oligomers are reacted with an epoxy resin. The invention consists of the advanced epoxy resins as well as cured compositions thereof.
Preparation of vinyl ester resin compositions containing triazine groups or both triazine and oxazoline groups is taught by R. E. Hefner, Jr. in allowed application Ser. No. 590,819 filed Mar. 19, 1984. In the process disclosed herein the respective triazine or triazine and oxazoline functional epoxy resins are reacted with a monounsaturated carboxylic acid. The invention consists of the vinyl esters and the vinyl ester and copolymerizable vinyl monomer formulations, whether or not cured.
Preparation of hydroxyaromatic oligomers containing triazine groups and ##STR2## linkages, otherwise called "imino carbamate" as well as epoxy resins and advanced epoxy resins thereof is taught in copending application Ser. No. 702,699filed of even date herewith, entitled "Hydroxyaromatic Oligomers of a Mixed Cyanate and Aromatic Polyamine and Epoxy Resins Thereof" by Robert E. Hefner, Jr. The oligomers are prepared by co-oligomerization of a mixed cyanate of a polyphenol with an aromatic polyamine in the process of this invention. Epoxidation of the oligomers and unreacted polyphenol, if any, using methods well known in the art provide epoxy resin compositions of this invention. Advancement reaction of the oligomers and unreacted polyphenol, if any, and an epoxy resin using methods well known in the art provide advanced epoxy resin compositions of this invention. The epoxy resin compositions of this invention possess enhanced mechanical properties, especially tensile strength and elongation.